Rotary drag bit



J. J. WHALEN ROTARY DRAG BIT Filed March 8, 1937' 3 Sheets-Sheet 1 J5 l1Jh/fia/m INVENTOR June 7, 1938.

J. J. WHALEN ROTARY DRAG BIT Filed March 8, 1937 3 Sheets-Sheet. 2

. K lull Ii I I INVENTOR June 7, 1938. wHALEN 2,119,661

ROTARY DRAG BIT Filed March 8, 1937 I5 Sheets-Sheet 5 Jase 0r) J 1460/80 INVENTOR ATTORNEY Patented June 7, 1938 UNITED STATES PATENTOFFICE 6 Claims.

This invention relates to a drill bit and more particularly to such abit employed in the drilling of deep wells by the rotary method. It hasbeen called a drag bit since it is not provided with 6 roller conecutters but with a chain type cutter having large plurality of teethwhich are adapted to scrape and saw the formation asthe bit bodyrotates.

When any one of several known particularly hard underground formationsare encountered in the drilling of a well, few bits of present designcan cut more than from two to ten feet into the formation before theybecome so dull as to be almost completely ineffective, even in softerformations. This necessitates the removal of the entire string of drillpipe and the replacing of the worn bit. When drilling'at a depth of4,000 feet, the replacing of a worn bit takes from five to nine hours intime, and in addition results in considerable wear and tear on thedrilling machinery, and thus shortens its life.

It is the chief object of my invention, therefore, to provide a bit theteeth of which, after they become worn, may be moved to an inoperativeposition and be replaced by new cutting teeth without the necessity ofwithdrawing the bit from the hole. This elimination of the necessity offrequently withdrawing the bit from the hole results in a large savingof time as well as the saving of much wear and tear on the drillingequipment.

Other objects of the invention are: to provide a bit having a largeplurality of cutting teeth, only a comparatively small number of whichperform the cutting function at any one time, and which small number maybe moved out of cutting position at will and replaced by other teeth inthe group, without removal of the bit from the hole; to provide a bit ofthe drag tooth type which presents so very large a number of teeth tothe form- 40 ation being cut that very little downward pressure on thebit is required. and consequently the hole is drilled much straighterthan by bits of present design; to provide a bit which is capable ofentering the drill hole, after having been withdrawn, without thenecessity of previously reaming the hole, thus saving considerable timewhich would otherwise be spent in reaming the hole, as well as savingconsiderable wear and tear on the drilling machinery; to provide a bit,the moving parts of which will last indefinitely, because they are heldstationary during the rotation of the bit in the hole; and which becauseof all the above features is more eflicient in drilling wells than bitsheretofore available to the oil trade.

Other objects of the invention will be seen from a consideration of thefollowing detailed description when read in connection with theaccompanying drawings which form a part of this ap plication.

Referring to the drawings:

Figure l is a side perspective view of the bit in drilling positionwithin a hole;

Figure 2 is a perspective view of one of the toothed links of which theendless chain is composed;

Figure 3 is a plan view of a portion of the endless chain showing themanner in which the toothed links fit together to form the chain;

Figure 4 is a side sectional view of the upper portion of the bitshowing particularly the construction of the fluid operated means formoving the endless chain, and for locking it against movement;

Figure 5 is a sectional view of the same portion of the bit as shown inFig. 4, but is taken at right angles to the Fig. 4 view, along the line55 of Fig. 1;

Figure 6 is a sectional view taken along the line 66 of Fig. 5 and showsmore clearly the relation of the chain and its driving sprockets;

Figure 7 is a sectional view taken along the line '|1 of Fig. 4 showingparticularly the manner in which the four longitudinal circulationpassages converge into two passages;

Figure 8 is a sectional view taken along the line 8-8 of Fig. 4 andshows the upper chain pulley together with the guide flanges at theouter edge of the chain way;

Figure 9 is a side perspective view of the lower end of the bit showingthe absence of teeth on some of the chain links as a means for allowingthe bit to re-enter the hole without the necessity for reaming the hole;

Figure 10 is a perspective view of the same portion of the bit shown inFig. 9, but is taken at right angles to the Fig. 9 view;

Figure 11 is a sectional view taken along the line H-l i of Fig. 13 andshows particularly the shape of the chain way;

Figure 12 is a sectional view taken along the line I 2-l2 of Fig. 10 andshows the lower chain pulley and the flanges for guiding the chain alongits way;

Figure 13 is a sectional view of the lower portion of the bit takenalong the line l3-|3 of Fig. 9 and shows particularly the manner ofmounting the lower chain pulley and the bit head on the bit body; and,

Figure 14 is a sectional view taken along the line l4-l4 of Fig. 5.

Like characters of reference designate like parts in all the figures.

Generally, my improved bit comprises an elongated bit body, an endlesschain with cutting teeth on its links, a pair of pulleys over which thechain moves, longitudinal guide ways formed in the sides of the bit bodyfor guiding the chain over the pulleys, a pair of sprockets for movingthe chain over the pulleys when desired, and for locking the chainagainst movement when desired; and fluid pressure means for moving andcontrolling the movement of the sprockets.

The bit body 20 is an elongated substantially cylindrical member but haslongitudinal water courses 2|, 22, 23, and 24 (Figs. 1 and 7) extendingsubstantially throughout its length, formed on its outer surface. It isalso provided interiorly with four longitudinally extending fluidcirculation courses 25, 26, 21 and 28 which extend from its upperthreaded end 29 to a point 30 intermediate its ends, where they convergewith two larger courses 3| and 32 by means of short cross ducts 33, 34,35 and 36, the outer ends of which are plugged, as shown in Fig.7. Thesetwo courses 3| and 32 extend longitudinally downward in the bit bodyfrom this point to the lower end of the bit (Fig. 13) where theycommunicate with hollow bolts 31 and 38 which serve to rigidly positiona bit head 39 on the lower end of the bit body.

In addition to the above the bit body 20 is also provided with a pair ofoppositely positioned longitudinally extending chain ways 40 and 4|, 2.cross sectional view of which, without the chain 42 is shown in Fig. 8,and with the chain in Figs. 7 and 11, and in which the chain moves andis guided.

Near its upper end the bit body 20 is provided with a pair ofperpendicularly intersecting longitudi nally extending slots 43 and 44,the offices of which will be hereinafter explained.

The lower portion of the slot 43 houses an upper chain pulley 45 (Figs.4, 5 and 8) which is journaled on a spindle bolt 46 (Fig. 5), the innerend of which is threaded into the bit stock, and the outer end of whichis hollowed as at 41 (see also Fig. 1) to receive a key (not shown) ofsimilar shape for removing the spindle from its seat.

A lower chain pulley 48 (Fig. 13) is rotatably mounted between thespaced lower ends of the bit head 39 on a spindle 49 which is held inposition by having its ends welded to the head, or by any other suitablemeans. Figs. 11 and 13 clearly show the cross sectional shape of theupper end of the bit head, which tightly fits into a suitably sizedsocket in the lower end of the body 2|). The entire head is rigidly heldin its socket in the lower end of the body 20 by means of the hollowbolts 31 and 38 which are screwed into the lower end of the-bit body,and the bores of which communicate with the circulation courses 3| and32, as previously explained.

Both the upper and lower pulleys are in alignment with each other andwith the chain ways 40 and 4|, so that the chain 42 is guided directlyover both pulleys, when it is moved. Figs. 10 and 12 show a chain wayidentical in cross section to the chain ways 40 and 4| formed around theouter edge of the head 39.

The endless chain 42 is composed of a plurality of links 50, one ofwhich is shown in Fig. 2, and all of which are provided on one side withsubstantially V-shaped lugs 5|. The inner edge of each link is arcuateto substantially conform to the edges of the pulleys 45 and 48, thisrelation being shown clearly in Fig. 12. The outer edges of the linksform a plurality of teeth 52. The various links are identical in shape.The teeth are of the same size, number and spacing on each link but areso located between the ends of the links that when the flat sides of twoof the links are placed together the points of the teeth on one of thelinks align with the valleys between the teeth on the other link, asclearly shown in Figs. 6 and 9. This arrangement pre sents a great manymore cutting teeth to the formation being drilled than if the points ofthe teeth aligned.

The cutting chain 42 is four links wide, the two center links beingpositioned with their fiat sides together, and the two connecting outerlinks being positioned with their lugged sides together, as shown inFig. 3. Removable pins 53 are used to fasten the adjacent ends of thelinks together, and these pins are of a length slightly less than thewidth of the chain ways 40 and 4| at their widest points (see Fig. 8),the sides of the ways thus preventing loss of the pins 53. A suitablenumber of adjacent blank" links are provided at some point in the chain,as shown in Fig. 12. With the chain in the position shown in thisfigure, it will easily be seen that the absence of teeth on these blanklinks sufliciently narrows the over-all size of the lower end of the bitto permit it to re-enter a hole after being withdrawn without thenecessity of first reaming the hole.

The mounting of the chain on the bit having been described, I will nowdescribe one means for controlling the movement of the chain over itspulleys. Referring to Figs. 4, 5 and 6, I provide a pair of identicalspaced sprockets 54 and 55, which are concentrically journaled withinthe slot 43 on a pin 56, so that they straddle the chain 42, and so thattheir adjacent teeth straddle the opposite protruding ends of the chainpins 53, as clearly shown in- Fig. 6. The teeth on these two sprocketsare so spaced that they contact each pin 53 as the chain moves over itspulleys. A second pair of gears 51 and 58 are spaced apart in exactalignment with the sprockets 54 and 55, and are concentrically keyed ona spindle 59, which in turn is journaled in the body walls. Between thetwo gears and also keyed to the spindle 59 by means of a key 60 (Fig. 4)is a ratchet wheel 6|. On their adjacent inner surfaces each of thegears 51 and 58 are provided with an inwardly extending circular hub (62and 63 respectively) which hubs serve to journal the spaced yokes 64 and65 of a crank arm 66, to the outer end of which is pivotally connectedone end of an operating link 61 which serves to rotate the crank arm 66about its axis. Intermediate its ends and between its spaced sides thecrank arm 66 pivotally carries a. pawl 68, which is in alignment withthe ratchet wheel 6|, and is adapted to contact the teeth of the ratchetwheel by gravity.

With this arrangement it may easily be seen by one skilled in the artthat when the operating link 61 is forced downward the crank arm 66 isforced to rotate on the hubs 62 and 63 (its axis) and as it rotates thepawl 66 will contact the teeth of the ratchet wheel 6| forcing theratchet wheel to rotate. In rotating, the ratchet wheel 6| rotates itsshaft 59 which in turn forces the rotation of the spaced gears 51 and58, which in turn rotate the sprockets 54 and 55, which move the chain42 over its pulleys.

The interrelation of the gears 51 and 58 and the sprockets 54 and 55will now be more fully described. As previously stated, the gears 51 and58 are respectively in vertical alignment with the sprockets 54 and 55and their respective axes are so spaced apart that the respective teethof the gears and sprockets are in mesh. The gears 51 and 58 have fewerteeth than the sprockets and between adjacent teeth the gears areprovided with arcuate blanks, all of which are designated by the numeral69.

In rotating, as one of the teeth on the gears leaves the valley betweentwo adjacent teeth on the sprockets, the edge of the following arcuateblank contacts only the tip of the next sprocket tooth, and by the timeit forces the tooth a very short distance (to the position shown in Fig.4) the edge of the blank 89 leaves the tip of the tooth. Furtherrotation of the gear, which incidentally requires very little power,causes the blank 69 to slide over the tips of the adjacent sprocketteeth to the position shown in Fig. 4, at which point further rotationof the gears is interrupted by means which will be hereinafterdescribed. When in this position the gears 51 and 58 are held againstaccidental movement in either direction preferably by leaf springs 10and ll, and 12 and 13 respectively (Figs. 4 and 6). The springs 10 and12 are identical, as are the springs "H and 13, and their curved endsmaintain a constant pressure against opposite edges of the gears 51 and58. Thus, after the gears have been moved to the locked position shownin Fig. 4, the crank arm 66 and its pawl 88 are free to return to theirnormal positions without the possibility of the gears 51 and 58 alsobeing rotated. In this position the gears 51 and 58 positively lock thesprockets 54 and 55, against rotation, and the chain 42 is thus heldagainst movement about its pulleys. The springs 10 and 72 are bothmounted on the inner surface of a plate 14 which is preferably welded tothe bit body 20, closing one end of the slot 43, from its upper end to apoint adjacent the location of the sprockets 54 and 55. Likewise theother end of the slot 43 is closed by a plate 15, which carries thesprings ll and 13 on its inner surface. These plates, however, are notplaced in position until after all of the above described means forcontrolling the movement of the chain has been assembled within the slot43.

The fluid pressure power means for operating the above described chaincontrolling mechanism will now be described. To the upper threaded end29 of the body 20 is connected a cylinder barrel 16, the lower portion11 of which is substantially the same in outside diameter as the body20. The upper portion 18 is reduced in diameter and its upper end isformed for connection to the drill pipe 19. The bore 88 of the lowerportion 11 is considerably larger than the bore 8! of the upper portion.Within the lower portion 11 is a cylindrical sleeve 82. the outer wallof which is spaced from the wall of the portion 11, leaving an annularspace therebetween. This sleeve 82 is integral with the lower end of theportion 18, the two together forming a cylinder. At the upper end of thesleeve 82 is provided a plurality of ports 83 and 84, which affordcommunication between the cylinder and the annular space between thesleeve and the portion 11. Intermediate its ends the upper portion 18 isprovided with an internal annular shoulder 85, which serves to limit thepenetration of the drill pipe 79 into its upper end, as well as to limitthe upward movement of a piston 86 in the cylinder.

The piston 86 has a small bore 81 through its upper end with a valveseat 88 formed at the inner end of this bore. The interior bore of thepiston is abruptly enlarged at this point to form a cage for a valve 89.The lower end of the valve 89 is of a diameter to permit it to easilyslide longitudinally within the enlarged bore of the piston. Theintegral valve head 98 is of a smaller diameter and is shaped to fit theseat 88. A plurality of longitudinal ports 9! and 92 affordcommunication between the space within the piston above the valve 89 andthe space below the valve 89. The valve 89 has a central threaded boreby means of which the upper end of the piston rod 93 is connected to thevalve, and indirectly to the piston. The lower end of the piston 88 isthreaded internally to receive an annular ring 94, which serves to limitthe movement of the valve 89 within the piston, yet which permits freeflow of fluid through the lower end of the piston when the valve isopen.

The upper end of the body 20 is centrally bored to form a guide for thepiston rod 93, the lower end of which extends into the slot 43 where itis connected pivotally to the uper end of the operating arm 81. Thiscentral bore is enlarged in its upper portion to accommodate a usualpacking gland 95 and packing gland nut 96 which serve to prevent leakageof fluid past the rod as it reciprocates. A coil spring 91 surrounds thepiston rod 93 within the cylinder barrel 18. Its upper end bears on thelower end of the piston and its lower end bears on the upper end of thebody 20, and it serves to normally hold the piston at the upper end ofits stroke. When the piston is at the upper end of its stroke the valvewithin the piston is necessarily open because the connection 98, whichis threadedly secured to the lower end of the piston rod 93, limits theupward movement of the rod 93, by contact with the top wall of the slot43, and consequently the upward movement of the valve 89 which isattached to its upper end.

This connection 98 is of a size to easily slide within the slot 43 asthe rod reciprocates, as is clearly shown in Fig. 5. It carries a guidepin 99, the ends of which protrude from either side of the connection98. These protruding ends travel in the slot 44 the sides of which thusguide the lower end of the piston rod 93 in its travel. The pin 99 alsoserves to pivotally connect the upper end of the operating arm 8'! inthe bifurcated lower end of the connection 98. After the pin 99 has beeninserted into the connection 98, and keyed in position by a cotter pinI00, the slot 44 is sealed at each end by plates Ifll and I02 (Figs. 1and 5) which may be welded or otherwise secured to the outer surface ofthe body 20.

Operation In operation the bit is secured to the lower end of the drillpipe in the usual manner, the blank links of its chain 42 being in theposition shown in Fig. 12. The bit is then lowered to the bottom of thewell. During its downward travel it is understood that the sprockets 54and 55, the arm 66, the gears 51 and 58, the piston 86, and its valve89, are in their normal inoperative positions. as in Fig. 4; and thechain is thus locked against movement over its pulleys. The valve 89,being open, permits circulation of fluid through the circulation courses3|, 32, 25, 26, 2'! and 28, through the ports 9| and 92, through bore 81and into the drill pipe 19.

When the lower end of the bit reaches the bottom of the well, fluidpressure is applied through the drill pipe 19. The fluid passes throughthe tension of the spring 91.

bore 81, and since neither this bore 8"! nor the ports 9| and 92 afforda sufliciently large outlet passage area to accommodate the full volumeof fluid, a pressure is created above the piston 86, forcing it downwardin its cylinder, against the When the piston has moved a short distancedownward, the valve 89 is closed, shutting off fluid circulation andplacing the full pump fluid pressure on the piston. As the pistontravels downward, the lower end of its rod 93 forces the operating link61 downward, which in turn moves the crank arm 68 toward the positionshown in Fig. 6, and thence to the position shown by the dotted lines ofFig. 4. The side pull on the lower end of the piston rod 93 is relievedby the pin 99 sliding vertically in its guide slot 44. As the crank arm66 rotates, it moves the gears 5'! and 58 as previously explained. Theblanks 69 are moved away from their locking contact with the adjacentteeth of the sprockets 54 and 55, and one of the long teeth on each gearthen contacts the teeth on the sprocket. As the sprockets 54 and 55 arerotated they move the chain 42 over its pulleys. After the long tooth oneach of the gears 51 and 58 leaves the respectively adjacent teeth onthe sprockets, the next arcuate blank 69 on the gears slides intolocking contact with the sprocket teeth, and the chain is again lockedagainst movement. The linkage of the piston with the gears 51 and 58 issuch that as the gears 51 and 58 again reach their normal positions, asin Fig. 4, with the crank arm still in the position shown by the dottedlines, the piston reaches the lower end of its stroke, and its upper endpasses the ports 83 and 84, opening them completely, and permitting thefluid to pass downward through the annular space between the sleeve 82and the lower portion of the barrel [6, through the circulation courses25, 26, 21, 28, 3| and 32, and out the lower end of the bit through thehollow bolts 31 and 38. The downward stroke of the piston is limited bythe contact of the pin 99 with the bottom of the slot 44. The excesspressure in the drill pipe 19 is easily suflicient to move the piston tothe extreme lower end of its stroke, even after the ports 83 and 84start to open, especially since the only work being performed by thepiston at this point in its travel is the sliding of the blanks 69 intolocked position. Friction, together with the tension of the spring 91against the further downward movement of the piston, is also easilyovercome by this excess pressure, so that the ports 83 and 84 willremain fully open so long as normal pump pressure is maintained. So longas the fluid pressure in the drill pipe is maintained the piston willremain at the lower end of its stroke, and consequently the link 61 andthe crank arm 66 will remain in the position shown by the dotted linesin Fig. 4. The drilling proceeds with the various parts in thisposition, and with the chain locked against movement, as shown.

When the fluid pressure is released, however, the crank arm 66 and itslink 61 return to the position shown by the solid lines in Fig. 4, andthe next time fluid pressure is applied the complete cycle of movement,as Just described, is repeated. The ratio of gearing between the ratchet6|, the gears 57 and 58, and the sprockets 54 and 55 is such that thechain moves a distance equivalent to the length of one link each timethe crank arm moves from the position shown in solid lines (Fig. 4) tothe position shown in dotted lines.

In ordinary drilling, this movement would bring a sufficient number ofnew teeth into contact with the formation. If desired to move the chaina greater distance over its pulleys, and thus bring, for instance, twocomplete new links of the chain into cutting position, it is onlynecessary to stop the fluid pressure and again apply it.

With further regard to the valve 89, it will also be noted that when thepump pressure is removed, the piston is returned to the upper end of itsstroke by the action of the spring 91, and that as it returns, the valve89 opens. If it is desired to withdraw the bit from the hole, therefore,the fluid in the drill pipe is free to drain through the piston valveand out through the circulation courses, as previously described.Sections of the drill pipe may thus be removed dry at the earth'ssurface.

It is believed that the manner of assembling of the various parts willbe entirely clear to one skilled in the art after having read the abovedescription in connection with the accompanying drawings. It istherefore considered suflicient to say only that when it is desired toreplace the chain 42, the spindle 46 is unscrewed and removed from thebit. Its removal permits the up per pulley 45 to drop to the bottom ofthe slot 43. The uppermost chain links are then free to drop downward inthe slot 43 so that the pins 53, in any one of the links, may be easilyaligned with a hole I83 in the bit body, in which position the pin maybe easily removed from the chain, and the chain separated. The chain maythen be easily removed through the lower end of the slot 43 (Fig. 6).

While I have described and illustrated a specific embodiment of myinvention, I am aware that it is capable of modification, and I do notwish to be limited except by the prior art and the scope of the appendedclaims.

I claim:

1, A device of the class described comprising: an elongated bit body; apair of pulleys rotatably mounted on said body; a cutter composed of aplurality of links fastened together to form an endless chain, each linkhaving a plurality of cutting teeth thereon; said cutter adapted to bemoved over said pulleys: ratchet operated gear and sprocket means formoving said cutter over said pulleys and also for locking it againstmovement over said pulleys; and power means carried by the body foroperating and controlling said last mentioned means.

2. A device of the class described comprising: an elongated bit body; apair of pulleys rotatably mounted on said body; a cutter composed of aplurality of links fastened together to form an endless chain, each linkhaving a plurality of cutting teeth thereon; said cutter adapted to bemoved over said pulleys; ratchet operated gear and sprocket means formoving said cutter over said pulleys and also for looking it againstmovement over said pulleys; and fluid pressure power means for operatingand controlling said last mentioned means.

3. A device of the class described comprising: an elongated bit bodyhaving a plurality of iongitudinally extending internal fluid passagestherethrough; a cutter pulley rotatably mounted in a through slot insaid bit body intermediate its ends; a bit head rigidly secured to thelower end of said bit body; a cutter pulley rotatably mounted in saidbit head; an endless chain type cutter mounted to move over saidpulleys; and means for moving said cutter over its pulleys and also forpreventing its movement over said pulleys.

4. A device of the class described comprising: an elongated bit bodyhaving a plurality of iongitudinally extending internal fluid passagestherethrough; a cutter pulley rotatably mounted in a through slot insaid bit body intermediate its ends; a bit head rigidly secured to thelower end of said bit body; a cutter pulley rotatably mounted in saidbit head; an endless chain type cutter mounted to move over saidpulleys; means for moving and controlling the movement 01' said cutterover its pulleys; and fluid pressure means for operating said lastmentioned means.

5. A device of the class described comprising: an elongated bit bodyhaving a plurality of iongitudinally extending internal fluid passagestherethrough; a cylinder barrel secured to the upper end of said bitbody, its bore in communication with said fluid passages; a cutterpulley rotatably mounted in a through slot in said bit body intermediateits ends; a bit head rigidly secured to the lower end of said bit body;a cutter pulley rotatably mounted in said bit head; an endless chaintype cutter mounted to move over said pulleys; means for moving andcontrolling the movement of said cutter over its pulleys; and a fluidpressure operated piston in said cylinder barrel for operating said lastmentioned means.

6. A device of the class described comprising: an elongated bit bodyhaving a plurality of iongitudinally extending internal fluid passagestherethrough; a cylinder barrel secured to the upper end of said bitbody, its bore in communication with said fluid passages; a cutterpulley rotatably mounted in a through slot in said bit body intermediateits ends; a bit head rigidly secured to the lower end of said bit body;a cutter pulley rotatably mounted in said bit head; an endless chaintype cutter mounted to move over said pulleys; means for moving andcontrolling the movement of said cutter over its pulleys; a fluidpressure operated piston in said cylinder barrel for operating said lastmentioned means; and a valve in said piston for controlling the flow offluid therethrough and through the fluid passages in said bit body.

JOSEPH J. WHALEN.

